Adafruit QT Py CH32V203 Dev Board with STEMMA QT

The Adafruit QT Py CH32V203 is a tiny, Xiao-compatible dev board featuring the low-cost, RISC-V-based CH32V203G6 microcontroller. It’s ideal for experienced developers exploring WCH’s ecosystem, with native USB, 10 ADC-capable GPIOs, I2C via STEMMA QT, and built-in NeoPixel — all in a compact, castellated form factor.

What a cutie pie! Or is it… a QT Py? This diminutive dev board from Adafruit features the powerful CH32V203 low-cost processor that’s all the trend: based on RISC-V and cheaper than an 8-bit core! This little one is a great way to get started in the CH32x processor family, with everything you need to build many USB-based projects at an excellent price. 

The CH32V203G6 has a single 32-bit RISC-V core, running up to 144MHz, with 1-cycle multiply/divide. Inside is 10KB SRAM, 32KB single-cycle Flash, as well as an additional ‘external XIP’ 224KB of Flash that can be used for program or data storage but is not as fast as the 32KB. There’s also extras you expect: ADC, timers, USB device, UART, I2C and SPI. 

However, please note that the CH32 series is not supported nearly-as-well as ATmega, ESP32, ATSAMD, STM32, or RP2040 chips that have a strong company-led development community. WCH is very ‘its a low cost chip, you figure it out’ kind of company, and while there is some community-led development it is still best used by folks comfortable with having to use Makefiles, clone git repositories, edit configuration files, etc. It definitely does not run CircuitPython or Micropython, and Arduino support is very early. It’s definitely not good for beginners! 

If you’re interested in playing with the CH32V203, we’ve wrapped it up in a QT Py format. The pinout and shape is Seeed XIAO compatible, with castellated pads so you can solder it flat to a PCB. It comes with our favorite connector – the STEMMA QT, a chainable I2C port that can be used with any of our STEMMA QT sensors and accessories. We also added an RGB NeoPixel and both a reset button and ‘bootloader enter’ button that allows you to upload code over USB without a WCH LINKE or similar SWD programmer.

Features

• Same size, form-factor, and pin-out as Seeed Xiao
• USB Type C connector
• CH32V203G6 RISC-V microcontroller core with 3.3V power/logic. Internal 144 MHz oscillator.
• Native USB Device – We do have USB CDC support via TinyUSB but its pretty chunky upload can also be done via USB
• Built in RGB NeoPixel LED
• 10 GPIO pins:
• ADC input on all GPIOs
• I2C port with STEMMA QT plug-n-play connector
• Hardware UART
• Hardware SPI
• 3.3V regulator with 600mA peak output
• Reset switch and bootloader switch for starting your project code over or entering
• USB ROM bootloader mode
• SWD data/clock pads on the bottom for advanced debugging usage
• Really really small

Resources

• Primary Guide: Adafruit QT Py CH32V203
• AP2112 datasheet

Package Contents

• 1x Adafruit QT Py CH32V203 Dev Board
• 1x 16-pin 2.54mm male header strip